In a spin injection writing type of magnetic memory, e.g., a spin-transfer torque magnetic random access memory (STT-MRAM), current necessary for magnetization reversal or a Magnetoresistive element is defined by a current density. That is, this type of magnetic memory has scalability in which the current necessary for magnetization reversal decreases in accordance with reduction of the size of the magnetoresistive element. Furthermore, if it is made to be of a vertical magnetization type in which a magnetization direction of residual magnetization of the magnetoresistive element is perpendicular to a film surface, the current necessary for magnetization reversal can be further decreased. For such a reason, the spin injection writing type of magnetic memory is one of odds-on favorites as a next-generation memory.
However, in order that a spin injection type magnetic memory be put to practical use, it is necessary to solve a problem of the magnetoresistive element with respect to processing. For example, the magnetoresistive element comprises a magnetic layer (storage layer) having variable magnetization, a magnetic layer (reference layer) having invariable magnetization and an insulating layer (tunnel barrier layer) between the above magnetic layers. This is a basic structure of the magnetoresistive element.